hi-8783 Holt Integrated Circuits, Inc., hi-8783 Datasheet - Page 3

• Manufacturer Part Number: hi-8783
• Description: 8 Bit Parallel Data In / Arinc Serial Data Out
• Manufacturer: Holt Integrated Circuits, Inc.

FUNCTIONAL DESCRIPTION (Cont.)
The HI-8784 and HI-8785 have the same digital logic func-
tion as the HI-8783, but include an on-chip line driver de-
signed to directly drive the ARINC 429 bus. The two ARINC
outputs (TXAOUT and TXBOUT) provide a differential volt-
age to produce a +10 volt One, a -10 volt Zero, and a 0 volt
Null. The slope of the ARINC outputs is controlled by the
SLP1.5 pin. If SLP1.5 is high, the output rise and fall time is
nominally 1.5us. If SLP1.5 is set low, the rise and fall times
are 10us. DATA ONE and DATA ZERO outputs are not pro-
vided for the HI-8784 and HI-8785.
The HI-8784 has 37.5 ohms in series with each line driver out-
put. The HI-8785 has 10.0 ohms in series. The HI-8785 is for
applications where external series resistance is needed, typi-
cally for lightning protection devices.
WRITE
DATA
BUS
A0
8
8 to 32 bit
counter
byte
mux
32
register
32 bit
buffer
XMIT CLK
Figure 1. Block Diagram
HOLT INTEGRATED CIRCUITS
HI-8783, HI-8784, HI-8785
32
register
status &
control
logic
32 bit
shift
3
POWER SUPPLY SEQUENCING
The power supplies must be controlled to prevent large
currents during supply turn-on and turn-off. The required
sequence is V+ followed by VDD, always ensuring that V+ is
the most positive supply. The V- supply is not critical and can
be asserted at any time.
A0
1
0
0
0
Figure 2. Order of transmitted bytes
Byte 1
Byte 2
Byte 3
Byte 4
Byte
word gap
counter
counter
bit
PARITY ENB
Data Bus
D0 - D7
D0 - D7
D0 - D7
D0 - D7
SLP1.5
output
driver
logic
line
ARINC 17 - ARINC 24
ARINC 25 - ARINC 32
ARINC 9 - ARINC 16
ARINC 1 - ARINC 8
ARINC Bits
HI-8784, HI8785
TXAOUT
TXBOUT
DATA ONE
DATA ZERO
XMT RDY
561 SYNC
561 DATA
HI-8783